Air-feeding apparatus for boiler-furnaces.



No. 634,348. Patented Oct. 3, I899. J. HOWDEN.

AIR FEEDING APPARATUS FOR BOILER FURNACES (Application filed May 2, 1899.)

-;No Model.) 2 Shaets-Sheet a; E 3' K WITNESSES f INVf/VTOR Jul, (U 1 u/mes flan/251v 17/5 HTTORNEYS.

Patented Oci. 3, I899.

J. Home".

AIR FEEDING APPARATUS FOR BOILER FURNACES.

(Application filed May 2, 1899.)

2 Shpets-Sheat 2 @No Model.)

WITNESSES:

l/IS HITORNEYS.

4? c2. j jbew' THE NORRIS vmzns cu, mo Ta-umo" WASHINGTON, u. c,

*r' TATES ATENT F-FICEEQ JAMES HOWVDEN, OF GLASGOW', SCOTLAND.

SPECIFICATION forming part of Letters Patent No. 634,348, dated October 3, 1899.

Application filed May 2, 1899- Serial No. 715,834:- (No model.)

To all whomit ntcty concern:

Be it known that I, JAMES HOWDEN, a subject of the Queen of Great Britain and Ireland, and a resident of Glasgow, Scotland, have invented new and useful Improvements in Air- Feeding Apparatus for Boiler-Furnaces, (for which I have applied for British Letters Patout, No. 21,194, dated October 8, 1898,) of which the following is a specification.

My said invention has for its object to provide improved apparatus for advantageously and satisfactorily applying my well-known system of forced draft to the furnaces of water-tube steam-boilers, my improvements being also applicable to what is known as induced-draft apparatus.

My improved apparatus may be adapted to various existing constructions of water-tube steam-boilers, two different types of boilers being by way of example shown on two accompanying sheets of explanatory drawings as fitted with my improvements.

Figure 1, Sheet 1,'is one-half an end elevation, the other half a partial vertical section. Fig. 2 is a horizontal section of air-heating apparatus, and Fig. 3 a vertical longitudinal section showing application of my improvements to one type of water-tube boiler. Figs. 4 and 5, Sheet 2, are a sectional front elevation and a vertical section showing application to another-namely, the Bellevilletype of water-tube boiler.

In the drawings the same reference-letters are used to mark the same or like parts wherever they are repeated.

In the case of the boiler shown in Figs. 1, 2, and 3, which comprises a longitudinal Water and steam drum or cylinder A, with tubes 13 extending down therefrom on each side to wator-boxes C, placed one along each side of a furnace D, which is below the drum A, I construct air-casings E at the sides of the drum A, such casings being provided with tubes F, up through which the fire-gases pass from inclosed spaces G at the outer sides of the Water-tubes B. The air-casings E are divided at about the middles II of their lengths, and air forced or drawn by a blower (not shown) enters at the middles H of the sides through a duct J and proceeds in separate streams to the front and back end of the drum A. In passing through the casings E the air crosses and is heated by the fire-gas tubes F, and its distribution over the surfaces of the tubes is rendered approximately uniform by horizontal diaphragms K. The diaphragms are, however, not always required.

At each end of the drum A the air-casings E communicate with the upper parts of spaces L, formed between the furnace-casing M of the boiler and outer metal shells N, and from the lower parts of these spaces the air passes, as hereinafter described, into'the furnace D above the grate and into-the ash-pit P.

The furnace D of such aboiler is usually of considerable length, and the flames and firegases proceed upward from all parts of the fire instead of fiowin g along, as in ordinary internal furnaces, and there is consequently an insufficient supply of air at the inner end of the furnace when the fire-doors Q are at one end only. To meet this difficulty, I arrange the air-heating casings E and the spaces L, as hereinbefore described, to supply air to cased spaces or distributing-boxes R r S at both. ends of the boiler, and in connection with the space S at the back of the boiler I provide valves T for admitting air above and below the grate at the back end of the furnace. These valves T at the back are connected by rods U to levers V for adjusting valves W, arranged at the front end of the boiler for admitting air to the ash-pit P, and the valves so connected are opened and closed together. At the front end additional valves X are arranged for admitting air to the part of the distributing-boxes R above the grate, the valves being adjustable by separate levers Y, as it is generally not necessary to close them when the other valves T IV are closed.

In a boiler such as is hereinbefore described I prefer to have two fire-doors Z at the end, and the internal furnace-space may be divided by a brick partition, so that when one firedoor is opened for coalin g the internal actions due to the opening of the door are confined to one internal compartment.

In other modifications of Water-tube boil ers I arrange the air-inlet valvesand the inclosed air-spaces to suit the particular arrangement in each case. In the modification ICC shown in Figs. l and 5 the air-heating casings E occupy space directly above the water-tubes l3, and the heated air descends through spaces L at the sides of the main furnace-casing of the boiler instead of at the ends, as in the first modification, the air proceeding from the lower ends of such spaces to the front and back ends of the furnace, and also to the side of the fire-space beneath the fire-grate D, the air-inlet valves being arranged and adjusted as shown.

The improved arrangements hereinbefore described,besides supplying heated air for the combustion of the fuel, and thereby securing a large economyin fuel, also prevent the great radiation of heat into the boiler-rooms from the casings of Water-tube boilers, and also the injuriously-high temperature of the fire-gases in uptakes and funnels, which necessarily occurs with the use of the closed-stokehold system of forced draft applied directly to the furnaces which has hitherto been generally used in such boilers.

\Vhat I claim as my invention is- Apparatus forsupplying and heating air for water-tube steam-boiler furnaces, comprising in combination means for forcing or drawing air through the apparatus and furnace-casings in which the air is heated, fire-gas tubes in the said casing, air-distributing boxes at the front and back ends and sides of the furnace, inclosed spaces to convey the air from the casing to the distributing-boxes and valves for controlling and regulating the distribution substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

\ JAMES HOWDEN.

\Vitnesses:

EDMUND HUNT, GEORGE PATTERSON. 

